Project Summary Modern drug discovery mandates the rapid and modular assembly of increasingly complex substances. Medicinally relevant molecules overwhelmingly bear nitrogen functionality with 910 of 1086 FDA small molecule drugs contain at least one N-atom. Of the Top 200 drugs by retail sales (2012), 73% are small- molecule based. Of these, 67% bear an aliphatic amine defined as having nitrogen not part of a heterocycle or aniline system. Functionalizing simple amine based precursors directly at C-H bonds is a significant problem. This proposal describes several strategies aimed at addressing this problem relying o complementary strategies to achieve the goal. The resultant products will facilitate the pace of drug discovery, with the common motifs visible in biologically active agents ranging from antibiotics, antidepressants among many others. The specific goals of this research are as follows: 1) Develop a unified protocol for ? functionalization of amines by 1,5 hydrogen atom transfer; 2) Exploit different directing groups on nitrogen to achieve complementary site selectivity; 3) Expand radical couples by merging cobalt and photoredox catalysis. The long-term impact of this science is to enable chemists to rapidly assemble complex structures with high efficiency.